Alloy.



James w. noun or EVANSIWN, ILLI'UOIS,

11 925 1133, Specification of letters Patent.

lie Drawing.

To (2 whom it may concern Be it known that 1, JAMES W DONNELL,.

that it resisted the action of metallic drills,

chisels and other tools. To circumvent this means of protection the burglar hasresortcl to the electric carbon pencil, which, by he action of fusion, will quickly perforate i rdest steel. This useof the electric encil was circumvented by safe makers by using electrically insulated metallic rods, plates, or other bodies incorporated in the walls of the safe so that, being insulated, when encountered by the electric pencil, they would interru t the electric current and stop the burnmg. This the burglar met by the use of a blow-pipe or torch burnir gases that produce a flame of intense heat, which required no electric circuit and operated fusing, burning, or otherwise decomposing the material of which the safe constructed. The problem now is to ovide a safe of such construction that it l he burglar proof in the sense'that it will resist all of the above mentioned methods and devices used by burglars, and particularly the torch, since this is now the means mostfrequently used and can do all that the other devices can do, and doit more tion or arrangement of said material or ma.-

zerials, may be perforated by some means or another if sufficient time be allowed for the operation, but it must be remembered that time is a ve important factor in the successful carrying out of a burglary. A dif ference of a few minutes or even seconds may amount to the difference between failure and success of the attempt, and hence anything that even hinders, delays and retards the operation of surreptitiously gaming access to the interior of a safe, to say Fatented May "7, 1912.

Application filed October 30, 1911. Serial 1%., 657,578.

nothing of altogether preventing it under the. circumstances and within the available time, is of vast importance in safe construction.

The object of the present invention is, therefore, to provide an alloy from which to make plates to be used in the construction of the walls or other parts of safes, having such properties that the operation of perforating them, and especially by the use of a torch, will be hindered and delayed as much as possible, so as to make it practically impossible of accomplishment within the time ordinarily available under the circumstances of a burglary.

To this end the invention consists inthe improved alloy to be used in the making of plates adapted to be used in constructing or "making the door or the wall of a safe, or to be incorporated therein, that will resist destruction by the action of a torch or an electric carbon pencil to the extent indicated. In selecting the materials for the alloy forming the plate, the principal properties to be. considered are fusibility, conductivity of heat and electricity and ductility, as the successful carrying out of the invention depends upon the resultant of these properties. More specifically stated the carrying out of the invention depends upon preventing the fusing or melting of the plate under the conditions available in a burglary;

As between, say, pure iron and copper, the iron is less fusible, z'.e., requires a more intense heat to fuse it, than the copper, and

if this property only were considered the iron would be the preferable of the two, for the purposes of the invention, but the heat or electric conductivity of copper is much greater than that of irons-so much greater that in carrying out the invention, copper is more efiective, This is because when the small flame of the torch is directed against a small localized spot of the plate, if the plate is wholly of iron the heat or electricity i conducted 0E yery slowly-and the fusing point of the iron at said spot is quickly reached and the plate dest royed j,'. whereas if 105 the plate is wholly of copper the'iheat of the a torch or a current of electricity-isfconducted away so rapidly that the copper itself does not'reach the fusing point, even at the small localized spot a ainst which the flame or 7 current plays. 0 it is with steel, instead of pure iron. But it is different with cast iron, which is not an elementary materialbut a compound contamingn'on andother I materials in a free state which are good conductors. Pure iron is difficultly fusible and a poor conductor of heat or electricity, but if "it contains also a suflicient uant-it-y of some other material that is a go conductor of heat, the compoundthe cast iron-becomes agood conductor of heat aswell as h ting a gh fusing point. For example,

white cast-iron and gray castiro n containing graphitic carbon in a free state have been found to be effective in carrying out the invention, the necessary heat or electrical conductivity being due to the presence of free graphitic carbon in the cast iron. There are many materials known to possess these properties to a greater or less degree, and' many of them could be used'in carrying out the invent1on,*but, of course, in order to be successful from a commercial point of view, the cost must be. taken into consideration. There are many materials on the market that .are suitable, but itis notnecessary for the purpose of this application to attempt a copper, which latter adds to the conductiv- "ity as well as the ductility of the plates,

and a small'proportion (say of l per cent.) of platinum, which still further adds to the conductivity and ductility of the alloy wearer I and also to 'it's resistanceto fusion, and this alloy is'worked'up into-plates of the desired thickness, which may be used in any desired manner in the construction of safes. They may be used for making the walls of the door, inwhole or in part, or they ma be incorporated in the-walls or door of w atever construction. In fact the inventionresides in the alloy itself and the plates made from it vmay be used many manner desired by the builderzv f e I am aware that it has heretofore been proposed to makean alloy ofcast iron or steel and copper, as a stepin the processes of making alloys of iron or steel andcopper, but, I' am not awarethat it has ever een discovered that the wall of a-safe orv other depository having, in its construction, a plateor plates made 'ofan alloy containing cast iron (being itself a compound co n taming iron and particles of free material which are good conductors of heat and elec tricit-y), copper and platinum will resist- 'fusion, thereby making the safe burglar proof to this extent,.and this discovery has never been applied, either practically or theoretically, in the making of safes burglar proo l What I claim as new and desire to secure by Letters Patent is'z, 3 I

An alloy containing cast iron,co'pper, and platinum in the proportions of about eighty per cen t.;.cast iron, about twenty per cent. copper ain't; about eight-tenths of one per cent. platinum, v JAMES W. DONNELL.

Witnesses:

J. M. Korma, L. M. Hornms, 

